/*
 * Copyright (c) 2019 The StreamX Project
 *
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.streamxhub.streamx.flink.repl.shell;

import org.apache.flink.annotation.Internal;
import org.apache.flink.api.common.InvalidProgramException;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.configuration.ConfigUtils;
import org.apache.flink.configuration.Configuration;
import org.apache.flink.configuration.DeploymentOptions;
import org.apache.flink.configuration.PipelineOptions;
import org.apache.flink.core.execution.JobClient;
import org.apache.flink.util.JarUtils;
import static org.apache.flink.util.Preconditions.checkNotNull;
import static org.apache.flink.util.Preconditions.checkState;

import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;


@Internal
public class ScalaShellEnvironment extends ExecutionEnvironment {

    /**
     * The jar files that need to be attached to each job.
     */
    private final List<URL> jarFiles;

    /**
     * reference to Scala Shell, for access to virtual directory.
     */
    private final FlinkILoop flinkILoop;

    public ScalaShellEnvironment(
        final Configuration configuration,
        final FlinkILoop flinkILoop,
        final String... jarFiles) {

        super(validateAndGetConfiguration(configuration));
        this.flinkILoop = checkNotNull(flinkILoop);
        this.jarFiles = checkNotNull(JarUtils.getJarFiles(jarFiles));
    }

    private static Configuration validateAndGetConfiguration(final Configuration configuration) {
        if (!ExecutionEnvironment.areExplicitEnvironmentsAllowed()) {
            throw new InvalidProgramException(
                "The RemoteEnvironment cannot be instantiated when running in a pre-defined context "
                    + "(such as Command Line Client, Scala Shell, or TestEnvironment)");
        }
        return checkNotNull(configuration);
    }

    @Override
    public JobClient executeAsync(String jobName) throws Exception {
        updateDependencies();
        return super.executeAsync(jobName);
    }

    private void updateDependencies() throws Exception {
        final Configuration configuration = getConfiguration();
        checkState(
            configuration.getBoolean(DeploymentOptions.ATTACHED),
            "Only ATTACHED mode is supported by the scala shell.");

        final List<URL> updatedJarFiles = getUpdatedJarFiles();
        ConfigUtils.encodeCollectionToConfig(
            configuration, PipelineOptions.JARS, updatedJarFiles, URL::toString);
    }

    private List<URL> getUpdatedJarFiles() throws MalformedURLException {
        final URL jarUrl = flinkILoop.writeFilesToDisk().getAbsoluteFile().toURI().toURL();
        final List<URL> allJarFiles = new ArrayList<>(jarFiles);
        allJarFiles.add(jarUrl);
        return allJarFiles;
    }

    public static void disableAllContextAndOtherEnvironments() {
        initializeContextEnvironment(
            () -> {
                throw new UnsupportedOperationException(
                    "Execution Environment is already defined for this shell.");
            });
    }

    public static void resetContextEnvironments() {
        ExecutionEnvironment.resetContextEnvironment();
    }
}
